Semi-automatic rifles, whether of the gas-operated type, with short or long recoil, or with pumping action are generally provided with a mechanism for feeding a fresh cartridge from the magazine of the weapon and delivering it to the cartridge chamber after the ejection of the cartridge case previously fired and subsequently to the cocking of the hammer.
Such a device comprises, as it is well known, a trowel-like lift which receives from the magazine a cartridge and delivers it subsequently toward the cartridge chamber, and a composite lever which cooperates with the trowel-like lift and changes from a position in which it blocks the cartridges within the magazine to a position in which it allows the passage of a cartridge at a time to the lift in synchronization with the action of the hammer upon the firing pin of the rifle.
One disadvantage is, however, possible with such a mechanism, in that the fresh cartridge might not be positioned timely in the trowel-like body of the lift for the subsequent feeding into the cartridge chamber, due to the recoiling action that follows the firing of a cartridge in the chamber and its ejection from the barrel of the rifle. The recoiling action has, in fact, the tendency of displacing the cartridges in the magazine in a forward direction and, thus, away from the lift, so that the passage of a fresh cartridge to the lift may be oftentimes incomplete or, at least untimely. This is especially true in the case of strong ammunition with consequent violent recoil. What happens then is a cycle of empty loading of the rifle, which finds itself with a cocked hammer, a closed breech block and an empty cartridge chamber, thus rendering the weapon unreliable in its intended use.